The study of evaporation dynamics of droplets is of scientific interest and has numerous practical applications. Here, we studied the evaporation of small condensate droplets on structured surfaces with one-tier microscale roughness and two-tier micro/nanoscale roughness (the top and valley of micropillars are covered by nanograss), respectively. On both surfaces, the micropillar arrays are arranged in a radical lattice with the decreasing pillar-to-pillar spacing towards the center of the surface (The first figures in Figs. 1 and 2). The condensate droplets on structured surfaces were formed by conducting condensation inside environmental scanning electron microscope (ESEM, Philips XL-30, ~4.9 Torr, stage temperature ~ 3°C). The condensate droplet on the one-tier surface stays in a Cassie-state (0 s in Fig. 1). However, owing to the preferential droplet nucleation on the smooth sidewall of micropillars, the condensate droplet on the two-tier surface maintains in the composite state (0 s in Fig. 2). To visualize the evaporation dynamics of condensate droplet, we gradually decreased the vapor pressure in the chamber from ~4.9 Torr to ~4.2 Torr. On the one-tier surface (Fig. 1), the droplet first evaporates in a constant contact radius mode (CCR, 0-124 s), followed by a constant contact angle mode (CCA, 136-166 s), and a mixed mode of both CCR and CCA (188-224 s). By contrast, on the two-tier surface (Fig. 2), the condensate droplet first evaporates in the CCR mode, with the solid-liquid contact line remain pinned until the formation of a flat liquid-air interface at the top of micropillars at ~86 s. After that, the liquid-air interface at the top of surface remains flat and the liquid evaporation is dominant in the lateral direction (96-170 s), with the liquid cylinder symmetrically shrinking towards the center of the surface. The presence of a stable and flat liquid/air interface at the top of surface is due to the stabilization effect rendered by the nanograss on the micropillars.